326 



NATURE 



[September 7, ign 



omething thai I13 from the living, 



the living from the dead. And John Hunter described his 



ci ption of it in words not very different from Driesch's, 



when he said that his principle, or agent, was independent 

 ul organisation, which yet it animates, sustains, and 



i' irs ; it was the same as Johannes Miiller's conception 

 ul an innate " unconscious idea." 



I ven in the Middle Ages, long before Descartes, we can 

 trace, if we interpret the language and the spirit of the 

 time, an antithesis that, if not identical, is at least parallel 

 to our alternative between vitalistic and mechanical hypo- 

 theses. For instance, Father Harper tells us that Suarez 

 maintained, in opposition to St. Thomas, that in genera- 

 tion and development a Divine interference is postulated, 

 by reason of the perfection of living beings ; in opposition 

 to St. Thomas, who [while invariably making an excep- 

 tion in the case of the human soul) urged that, since the 

 existence of bodily and natural forms consists solely in 

 their union with matter, the ordinary agencies which 

 operate on matter sufficiently account for them. 1 



But in the history of modern science, or of modern 

 physiology, it is, of course, to Descartes that we trace the 

 origin of our mechanical hypotheses — to Descartes, who, 

 imitating Archimedes, said, "Give me matter and motion, 

 and I will construct the universe." In fact, leaving the 

 more shadowy past alone, we may say that it is since 

 Descartes watched the fountains in the garden, and saw 

 the likeness between their machinery of pumps and pipes 

 and reservoirs and the organs of the circulation of the blood, 

 and since Yaucanson's marvellous automata lent plausi- 

 bility to the idea of a " living automaton " — it is since 

 then that men's minds have been perpetually swayed by 

 one or other of the two conflicting tendencies, either to 

 seek an explanation of the phenomena of living things in 

 physical and mechanical considerations, or to attribute 

 them to unknown and mysterious causes, alien to physics 

 and peculiarly concomitant with life. And some men's 

 temperaments, training, and even avocations, render them 

 more prone to the one side of this unending controversy, 

 as the minds of other men are naturally more open to the 

 other. As Kiihne said a few years ago at Cambridge, the 

 physiologists have been found for several generations lean- 

 ing, on the whole, to the mechanical or physico-chemical 

 hypothesis, while the zoologists have been very generally 

 on the side of the Vitalists. 



The very fact that the physiologists were trained in the 

 school of physics, and the fact that the zoologists and 

 botanists relied for so manj years upon the vague, un- 

 defined force of " heredity " as sufficiently accounting for 

 the development of the organism, an intrinsic force the 

 results of which could be studied, but the nature of which 

 seemed remote from possible analysis or explanation — these 

 facts alone go far to illustrate and to justify what Kiihne 

 said. 



Claude Bernard held that mechanical, physical, and 

 chemical lours summed up all with which the physiologist 

 has to deal. Verworn defined physiology as " the chem- 

 istry of the proteids " ; and I think that another physio- 

 logist (but I forget who) has declared that the mystery of 

 life lay hidden in "the chemistry of the enzymes." But 

 ol late, as Dr. Haldane showed in bis address a couple of 

 ago to the Physiological Section, it is among the 

 physiologists themselves, together with the embryologists, 

 thai we find the strongest indications of a desire to pass 

 beyond the horizon of Descartes, and to avow that physical 

 and chemical methods, the methods of Helmholtz, Ludwig, 

 and Claude Bernard, fall short of solving the secrets of 

 physiology. On the other hand, in zoology, resort to the 

 method of experiment — the discovery, for instance, of thi 

 wonderful effects of chemical or even mechanical stimula- 

 tion in starting the development of the egg— and 

 the ceaseless search into the minute structure, or so-called 

 mechanism, of the cell- -these, 1 think, have rather tended 

 to sway a certain number of zoologists in the direction of 

 lianical hypothesis. 



1 excedant 



'urn naturalium et corporal 

 imione ad materiam ; ejusdem agentis 

 transmutare. Sec undo, iuia 

 m et ordinem et facilitate!!) pri 



• orum originem in prilicipia rediicere altiora.— Aq'u 

 Q 111., a, 11: cf. Harper, " Metaphj ics if the School," iii. 1, p. 15 



NO. 2184, VOL. 87] 



..-; non consistat ni: 

 videtur eas producere, cujus est 



mi hujusi li I 



intium in 



But, on tin wholi , 1 think it is very manifest that there 

 is abroad on all sides a greater spirit of hesitation and 

 caution than ul old, and that the lessons of the philosophi 1 

 have had their influence on our minds. VVi realise that 

 the problem ol development is far harder than we had 

 begun to lei ourselves supposi . that the problems of 

 organogeny and phylogenj (as well as those of physio- 

 logy) are not comparatively simple and well-nigh solved, 

 but are of the most formidable complexity. And we would, 

 most of us, confess, with the learned author of " I he Cell 

 in Development and Inheritance," " that we an utterly 

 ignorant of the manner in which the substance ol the 

 germ-cell can so respond to the influence of the environ- 

 ment as to call forth an adaptive variation; and again, 

 that the gulf between the lowest forms of life and the 

 inorganic world is as wide as, if not wider than, it seemed 

 a couple of generations ago." 1 



While we keep an open mind on this question of 

 Vitalism, or while we lean, as so many of us now do, or 

 even cling with a great yearning, to the belief that some- 

 thing other than the physical forces animates and sustains 

 the dust of which we are made, it is rather the business 

 of the philosopher than of the biologist, or of the biologist 

 only, when he has served his humble and severe apprentice- 

 ship to philosophy, to deal with the ultimate problem. It 

 is the plain bounden duty of the biologist to pursue his 

 course, unprejudiced by vitalistic hypotheses, along the road 

 of observation and experiment, according to the accepted 

 discipline of the natural and physical sciences ; indeed, I 

 might perhaps better say the physical sciences alone, for 

 it is already a breach of their discipline to invoke, until 

 we feel we absolutely must, that shadowy force of 

 " heredity " to which, as I have already said, biologists 

 have been accustomed to ascribe so much. In other words, 

 it is an elementary scientific duty; it is a rule that Kant 

 himself laid down 2 that we should explain, just as far 

 as we possibly can, all that is capable of such explanation 

 in the light of the properties of matter and of the forms 

 of energy with which we are already acquainted. 



It is of the essence of physiological science to investi- 

 gate the manifestations of energy in the body, and to refer 

 them, for instance, to the domains of heat, electricity, or 

 chemical activity. By this means a vast number of pheno- 

 mena, of chemical and other actions of the body, have 

 been relegated to the domain of physical science and with- 

 drawn from the mystery that still attends on life : and by 

 this means, continued for generations, the physiologists, 

 or certain of them, now tell us that we begin again to 

 descry the limitations of physical inquiry, and the region 

 where a very different hypothesis insists on thrusting itself 

 in. But the morphologist has not gone nearly so far as 

 the physiologist in the use of physical methods. He sees 

 so great a gulf between the crystal and the cell, that the 

 very fact of the physicist and the mathematician being 

 able to explain the form of the one, by simple laws of 

 spatial arrangement where molecule fits into molecule, 

 seems to deter, rather than to attract, the biologist from 

 attempting to explain organic forms by mathematical or 

 physical law. Just as the embryologist used to explain 

 everything by heredity, so the morphologist is still inclined 

 to say — " the thing is alive, its form is an attribute of 

 itself, and the physical forces do not apply." If he does 

 not go so far as this, he is still apt to take it for granted 

 that the physical forces can only to a small and even 

 insignificant extenl Mend with the intrinsic organic forces 

 in producing the resultant form. Herein lies our question 

 in a nutshell. Has the morphologist yet sufficiently studied 

 the forms, external and internal, of organisms in the light 

 of the properties of matter, of the energies that are 

 associated with it, and of the forces by which the actions 

 of these energies may be interpreted and described? Has 

 the biologist, in short, fully recognised that there is a 

 borderland, not only between physiology and physics, but 

 between morpholep and physics, and that the physicist 

 may. and must, be his guide and teacher in many matters 

 ding organic form? 



Now this is by no means a new subject, for such men 

 as Berthold and Errera Rhumbler and Dreyer, Biitschli 

 and Verworn, Driesch and Roux, have already dealt or 



t Wilson, <>/. cit. 150'. p. ; i ueofTeleo'ogical I 



